Stamping an image onto an object?

I have a book model that just floats in midair, but I wanted to add a symbol onto it. I have a transparent image of my symbol and I thought there was a way to just "stamp" it onto the front of the book object. Does anyone have any idea how I could do this?

Change the texture of the cover mesh of your book model to your image.

Create a GUITexture, then assign your image to the GUITexture, then position your GUITexture gameobject onto the book, then make the GUITexture game object a child of your book object.

GUITexture is located under GameObject -> Create Other -> GUI Texture

EDIT: To make a GameObject (Something in the Hierarchy) a child of another, drag the child gameObject onto the parent.